Interpolymerization of olefins



Patented Feb. 17, 1948 2,43 ,338 mrsaronmnarzarron or omrnvs Edward F. Wadley and- Joseph T. Horeczy, Baytown, Tex., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application November 4, 19 44; Serial No. 562,022

11 Claims.

The present invention is directed to a process for the 'interpolymerization of olefins of difierent molecular weight.

Hitherto, polymerization and copolymerization of olefins has been carried out with commercial success primarily with C4 olefins. Many attempts have been made to utilize the lighter olefins tor the production of liquid hydrocarbons by polymerization or by interpolymerization thereof with heavier olefins. When it was attempted to eflect such interpolymerization, as for example of propylene with pentylene, in the presence of sulfuric acid as a catalyst, the yield and/or the quality of the polymer produced proved unsatisfactory. Attempts have been made to polymerize the lower olefins by the catalytic action of boron fluoride. These have resulted in the production of high boiling liquids which are not adaptable to commercial uses without modification.

It has now been discovered that interpolymerization of olefins of different molecular weights may be achieved readily and satisfactorily when the reaction is conducted in the presence of a mixed catalyst containing boron fluoride and suliuric acid at suitable temperatures and pressure. The particular virtue of the process of the present invention is that it makes possible the production of high yields of Ca hydrocarbons from pentylenes and propylene. The conditions of operation can be so adjusted-as to favor the production of Ca hydrocarbons from these starting materials over the production of hydrocarbons of higher molecular weights.

The process of the present invention is applicable to the most diverse types of mixed olefinic feeds. Because of the great demand for butylenes in other refinery processes, the process or the present invention is more desirably applied to the interpolymerization of olefins with less than 4 carbon atoms with those of more carbon atoms.

The process, when applied to mixtures of C: and C4 olefins, however, does produce interesting Cr olefins, the branchiness of which may be influenced by suitable selection of the C4 olefin. Among the C1 olefins, one of particular value is be employed. Acid 01 strength'above' '80% iniiuences the reaction in the direction of formation 01' heavy polymer; An amount of BF: below 5% gives a mixture which istoo weak in catalytic activity, while an amount above 25% renders the mixed catalyst over-active and unstable... a

The process of the present invention is preferably conducted inthe liquidnphase at temperatures between about 125 and 175 1". While the lower temperature limit given is fairly rigid, because lower temperatures increase the content of heavy ends in the product undesirably. the upper limit given is one imposed'by material limitations, since above this upper limit corrosion difliculties are multiplied. If non-corrosive equipment' is available, temperatures up to 250 or even 300 F, can be employed, and in fact the higher the temperature the more favorably influenced is the product with respect to content of Ca hydrocarbons where propylene and pentylone are employed as starting materials. Since it is desired to conduct the reaction in liquid phase,

cess over the mixed catalyst, but a volume ratio of hydrocarbon to catalyst as low as 0.5 to 1 is permissible. In general, this ratio will not exceed 15 to 1. As to the hydrocarbonieed itself, it

2,3,3-trimethyl-1-butene, which is assuming conmay be generally stated that the lower olefin should be in molar excess of the higher. For example, when propyleneand pentylene are employed, it is preferable to have the. propylene. in molar excess by a ratio of 3 to 1 or higher.

In carrying out the process of the present invention, the same technique is followed as is customary in polymerization, alkylation and isomerization reactions in which hydrocarbons are caused to react by being contacted with a liquid catalyst. The various expedients employed to regulate contact times in these various other processes are applicable to the present process. More specifically, the emulsion type reaction commonly employed in alkylation is admirably suited for carrying out theprocess oi the present invention. The contact or reaction time may vary from 15 to minutes. This reaction time is shorter, the higher the temperature, and in the upper end of the operative temperature range may be as low as 5 minutes.

As an example of suitable operatingconditions, product character and yield characteristic of the process of the present invention, reference is bad to the following table giving the pertinent data with respect to a plurality of runs.- In these runs suiiicient pressure was employed to maintain the reactants in the liquid phase at the operating temperature.

Run No Com gosltion of Catalyst:

t. per cent BF: Wt. per cent B:S| Composition of Hydrocarbon Charge:

Moles of C's/Ci Reaction Temperature, F. Catalyst 'lreat:

Vol. Hydrocarbon/Vol.

Catalyst Reaction Time, Minutes Estimated Polymer Yield (C;

iree basis):

Wt. per cent Based on Oleflns Engler Distillation of Polymer: 13 F Per cent on at 240 F Per cent of! at 320 F I l Separation of product incomplete;

The polymers from all runs were combined and submitted to a precise distillation such as the socalled Fenske distillation. The Fenske distillation indicated the polymer to be composed primarily of Ca olefins andCio olefins (62.5 volume per cent Ca olefins). The Ca fraction of the polymer was hydrogenated and the octane blending value of the hydrogenated fraction obtained. This was done by blending the hydrogenated Ca fraction with isopentane to a 7-pound R. V. P. and then blending 40% of the 7-pound blended hydrogenated polymer with of 99.! octane number reference fuel. The 1-0 blending value of the hydrogenated Ca fraction (l-pound basis) was found to be 101.

In addition to these runs, another was carried out employing 50% H2804 containing 15.6 weight per cent BF: as catalyst. In this run the polymer was found to contain about volume per cent oi Ca and lighter hydrocarbons.

In addition to the runs previously mentioned, two other runs were carried out which show that Co hydrocarbons can be easily produced by employing a BF3su1furic acid mixture as catalyst. In these runs 65% sulfuric acid was added. Polymerization temperatures of 150 to 175 F. were employed. The analysis of the polymer was estimated from a Fenske distillation curve and is given below:

The components of the Ca fraction estimated from Fenske boiling points, refractive indlcies, and specific gravity. are given below:

Volume Component Per Cent 01' 1 Fraction Dimethyl Hexane Trimethyl Pentanes The octane rating of the Ca fraction was obtained by blending it with 25 volume per cent lso- 1 5. A method according to claim 2 in pentane and then blending it in 40% concentrations in 99.7 octane number reference fuel.- The ASTM aviation plus 4 cc. TEL (1-0) blending value of the Ca fraction was found to be 103.5.

In another operation propylene was interpolymerized with isobutylene. The catalyst was composed oi weight per cent of 65% H2804 and 15 weight per cent of boron trifluoride. .The mole ratio of propylene to isobutylene in the feed stock 10 was 5.5 to 1 and the volume ratio of the hydrocarbon ieed to the catalyst was 4 to 1. The reaction time was 30 minutes. during which the temperature rose from to 160 F.

After separation of the polymer from the acid.

15 the former was stabilized to eliminate any Ca and C4 hydrocarbons. In order to obtain the distillation characteristics of the stabilized polymer, a careful fractionation was conducted with the following results:

Vol. Pel' Cent Stabilized Polymer I and Br. No.

Taken 0. H. F B or of Cut Out, F.

I. B. P. to 5% 158-174 a to 287 174-178 15c 28 to as 178-197 as to s 197-205 114.5 so to as 205-208 173. 2 58 to 64 208-210 168. s 64 m 12%. 210-218 12 to 767 218-308 76 to 92 aoeaso 92 to 99% 350-396 The data indicate about 64 volume per cent of the stabilized polymer to be C1 hydrocarbons.

From the foregoing it will be observed that by the process of the present invention eifective interpolymerization of olefins of different molecular weights can be realized. It will be recognized that the conditions of operation are capable of so extensive variation and that various combinations of olefins may be employed as feed stock. It is to be understood that the specific operations reported arefor illustrative purposes only, and are not intended to confine the scope oi the present 46 invention.

The nature and objects of the present invention having been fully described, what we desire to claim as new and useful and to secure by Letters Patent is:

60 -1. A method for interpolymerizing olefins of different molecular weights which comprises contacting these olefins in admixture with each other with a mixture of boron fluorideand sulfuric acid or a concentration between about 50% and 80%,

55 of which mixture the boron fluoride constitutes between about 5 and about 25 weight per cent, at a temperature between about F. and 300 F. for a period sufiicient to effect the desired reaction.

2. A method for interpolymerizing Ca and Ca olefins which comprises contacting these olefins in admixture with each other with sulfuric acid of a concentration between about 50% and 80% containing from 5 to 25% by weight "of bo'ron o5 fluoride at a temperature between about125 F.

and 300 F. for a period suihcient to eflect the desired reaction.

3. A method according to claim 1 in which the olefin of lower molecular weight is used iii-molar n, excess relative to the olefin of higher molecular weight.

4. A method according to claim 2 in which the mole ratio of Ca olefin to C5 olefin is at least 3 to 1.

we the 1 w cm e fcilowing referees e at ceccm it e cemticntcthe 1;; t a ,1. I. A method according to cl 2 Eh;- which the cl feet? is mamtainec in volumetric excess 3 with relation to the ceiyst. c. A method according to claim 21 in Meta the 0m ctmtcct e is between about 15 W minutes. ac 2399380 mugmm c. A method according to claim 2 in which the 2302159 Stevens contact time is between about 15 c mum. 232

m, A ethm for g etc of erect moiecular weightc, each of which cow mnb t1, are then two carbon etc, which N 3 prices contacting these ole in p: 1.1. 1 mfigg eech iv with c w I t 1: oi bomn flucride and tulfuric acid of c concentmfl between a L598 50% em 30%, of which mixture e cc fluccide ctitu between ebout e a c $5 weht film: at a cent, at c t tw "ifefi F 5474549 and about 800 for a period the ti cticn.

11. A math mm: to the 01 't r 

